Find out what page cloaking is, why it is used, and whether or not you should use it.

Page cloaking can broadly be defined as a technique used to deliver different
web pages under different circumstances. There are two primary reasons that
people use page cloaking:

i) It allows them to create a separate optimized page for each search engine
and another page which is aesthetically pleasing and designed for their
human visitors. When a search engine spider visits a site, the page which
has been optimized for that search engine is delivered to it. When a human
visits a site, the page which was designed for the human visitors is shown.
The primary benefit of doing this is that the human visitors don't need
to be shown the pages which have been optimized for the search engines,
because the pages which are meant for the search engines may not be aesthetically
pleasing, and may contain an over-repetition of keywords.

ii) It allows them to hide the source code of the optimized pages that
they have created, and hence prevents their competitors from being able
to copy the source code.

Page cloaking is implemented by using some specialized cloaking scripts.
A cloaking script is installed on the server, which detects whether it is
a search engine or a human being that is requesting a page. If a search
engine is requesting a page, the cloaking script delivers the page which
has been optimized for that search engine. If a human being is requesting
the page, the cloaking script delivers the page which has been designed
for humans.

There are two primary ways by which the cloaking script can detect whether
a search engine or a human being is visiting a site:

i) The first and simplest way is by checking the User-Agent variable. Each
time anyone (be it a search engine spider or a browser being operated by
a human) requests a page from a site, it reports an User-Agent name to the
site. Generally, if a search engine spider requests a page, the User-Agent
variable contains the name of the search engine. Hence, if the cloaking
script detects that the User-Agent variable contains a name of a search
engine, it delivers the page which has been optimized for that search engine.
If the cloaking script does not detect the name of a search engine in the
User-Agent variable, it assumes that the request has been made by a human
being and delivers the page which was designed for human beings.

However, while this is the simplest way to implement a cloaking script,
it is also the least safe. It is pretty easy to fake the User-Agent variable,
and hence, someone who wants to see the optimized pages that are being delivered
to different search engines can easily do so.

ii) The second and more complicated way is to use I.P. (Internet Protocol)
based cloaking. This involves the use of an I.P. database which contains
a list of the I.P. addresses of all known search engine spiders. When a
visitor (a search engine or a human) requests a page, the cloaking script
checks the I.P. address of the visitor. If the I.P. address is present in
the I.P. database, the cloaking script knows that the visitor is a search
engine and delivers the page optimized for that search engine. If the I.P.
address is not present in the I.P. database, the cloaking script assumes
that a human has requested the page, and delivers the page which is meant
for human visitors.

Although more complicated than User-Agent based cloaking, I.P. based cloaking
is more reliable and safe because it is very difficult to fake I.P. addresses.

Now that you have an idea of what cloaking is all about and how it is implemented,
the question arises as to whether you should use page cloaking. The one
word answer is "NO". The reason is simple: the search engines
don't like it, and will probably ban your site from their index if they
find out that your site uses cloaking. The reason that the search engines
don't like page cloaking is that it prevents them from being able to spider
the same page that their visitors are going to see. And if the search engines
are prevented from doing so, they cannot be confident of delivering relevant
results to their users. In the past, many people have created optimized
pages for some highly popular keywords and then used page cloaking to take
people to their real sites which had nothing to do with those keywords.
If the search engines allowed this to happen, they would suffer because
their users would abandon them and go to another search engine which produced
more relevant results.

Of course, a question arises as to how a search engine can detect whether
or not a site uses page cloaking. There are three ways by which it can do
so:

i) If the site uses User-Agent cloaking, the search engines can simply
send a spider to a site which does not report the name of the search engine
in the User-Agent variable. If the search engine sees that the page delivered
to this spider is different from the page which is delivered to a spider
which reports the name of the search engine in the User-Agent variable,
it knows that the site has used page cloaking.

ii) If the site uses I.P. based cloaking, the search engines can send a
spider from a different I.P. address than any I.P. address which it has
used previously. Since this is a new I.P. address, the I.P. database that
is used for cloaking will not contain this address. If the search engine
detects that the page delivered to the spider with the new I.P. address
is different from the page that is delivered to a spider with a known I.P.
address, it knows that the site has used page cloaking.

iii) A human representative from a search engine may visit a site to see
whether it uses cloaking. If she sees that the page which is delivered to
her is different from the one being delivered to the search engine spider,
she knows that the site uses cloaking.

Hence, when it comes to page cloaking, my advice is simple: don't even
think about using it.

About the Author
Sumantra Roy is one of the most respected and recognized
search engine positioning specialists on the Internet. For more articles
on search engine placement, subscribe to his first Search Ranking Newsletter
by going to: http://www.the-easy-way.com/newsletter.html.